High-performance crystalline bio-based polyurethane elastomer as well as preparation method and application thereof

Abstract

The invention discloses a high-performance crystalline bio-based polyurethane elastomer as well as a preparation method and application thereof. The preparation method comprises the following steps: at least carrying out polymerization reaction on a levulinic acid derivative, polycaprolactone diol, isocyanate, polycaprolactone triol and a catalyst to prepare the high-performance crystalline bio-based elastomer, wherein the levulinic acid derivative comprises a diamine structure. According to the prepared high-performance crystalline bio-based elastomer, the crystallization performance of the elastomer can be influenced by changing the ratio of the raw materials, and then the mechanical performance of the elastomer is influenced. In addition, dynamic carbamate bonds in the structure can realize reprocessing and use of the elastomer, and green development of the elastomer is realized.

Description

Technical Field

[0001] This invention belongs to the field of polyurethane technology, specifically relating to a high-performance crystalline bio-based polyurethane elastomer, its preparation method, and its application. Background Technology

[0002] Crosslinked elastomers have been widely used in our daily lives due to their excellent properties. They are commonly used as corrosion-resistant coatings in materials such as wood and leather, especially polyurethane crosslinked elastomers. Polyurethane elastomers are a class of elastomer materials whose molecular backbone contains repeating urethane groups (-NHCOO-). They are polymerized from polyols and isocyanates, possessing some characteristics of both rubber and plastics. They exhibit high elasticity at room temperature while also possessing certain strength and hardness properties of plastics. Their unique structure and properties have attracted much attention. Moreover, by changing the types and ratios of polyols and / or isocyanates, applications such as building materials, transportation materials, food packaging materials, and medical materials can be designed to meet specific needs, including adhesives and foams.

[0003] However, the proportion of monomers used in the synthesis of polyurethane in existing technologies heavily relies on petroleum-based raw materials. On the one hand, this may lead to resource shortages; on the other hand, the cross-linked structure of the elastomer can cause it to be non-recyclable, resulting in environmental pollution; and thirdly, the simple polyurethane structure is limited by its structure and cannot further meet people's usage needs. Therefore, designing high-performance bio-based elastomers using bio-based monomers is of great significance for environmental protection, resource utilization, and even product diversity. Chinese invention patent CN1 16589722A discloses a method for preparing a high-strength, high-transmittance bio-based polyurethane film, which involves mixing malic acid and aromatic ring diols, adding isocyanate for end-capping, and then adding a chain extender to polymerize and obtain bio-based polyurethane with strong light transmittance. Chinese invention patent CN119119414A discloses a thermoplastic polyurethane elastomer using bio-based polyisocyanate as a raw material, resulting in an elastomer with biodegradability and a glass transition temperature of 20–50°C. The polyurethane elastomers obtained by the above technical solutions all have relatively poor crystallinity, and their mechanical properties cannot meet the requirements of existing polyurethane products.

[0004] Based on this, the present invention provides a high-performance crystalline bio-based elastomer, which is a polyurethane elastomer synthesized from bio-based raw materials that not only has high strength and high crystallinity but also excellent mechanical properties. Summary of the Invention

[0005] The main objective of this invention is to provide a high-performance crystalline bio-based elastomer, its preparation method, and its application, in order to overcome the shortcomings of the prior art.

[0006] To achieve the aforementioned objectives, the technical solution adopted by this invention includes:

[0007] This invention provides a method for preparing a high-performance crystalline bio-based elastomer, the specific steps of which include: polymerizing a levulinic acid derivative, polycaprolactone diol, isocyanate, polycaprolactone triol and a catalyst to obtain a high-performance crystalline bio-based elastomer; wherein the levulinic acid derivative contains a diamine structure.

[0008] Preferably, the levulinic acid derivative is 4,4′-bis(5-amino-2-furanyl)valerate. Preferably, the levulinic acid derivative includes, but is not limited to, methyl 4,4′-bis(5-amino-2-furanyl)valerate, ethyl 4,4′-bis(5-amino-2-furanyl)valerate, etc. 4,4′-bis(5-amino-2-furanyl)valerate is a compound synthesized based on bio-based monomers. For example, methyl 4,4′-bis(5-amino-2-furanyl)valerate can be prepared by reacting methyl valerate with a compound containing a 5-amino-2-furanyl group. The 5-amino-2-furanyl compound is a bio-based monomer, which, on the one hand, reduces the dependence on petroleum-based compounds in synthesis, effectively addressing the current predicament of excessive reliance on petroleum-based raw materials in polyurethane. On the other hand, the furan ring structure in the synthesized compound not only possesses certain antibacterial activity, but also may undergo photochemical reactions under light, thereby initiating the decomposition of the entire molecule and achieving molecular degradation, improving the environmental friendliness and safety of polyurethane products. Therefore, the polyurethane elastomer provided by this invention can be used in building materials, transportation materials, food packaging materials, or medical materials. In particular, it can be used in the processing and preparation of food packaging materials, medical materials, such as medical catheters.

[0009] The present invention also provides isocyanate-terminated prepolymers prepared by the aforementioned preparation method.

[0010] Preferably, the preparation method specifically includes: dehydrating the polycaprolactone diol, adding isocyanate and catalyst, and reacting for 3-5 hours to obtain an isocyanate-terminated prepolymer.

[0011] Preferably, the dehydration includes evacuating the vacuum at 100-110°C for 1-2 hours and then cooling the temperature to 60-80°C.

[0012] Further, the obtained isocyanate-terminated prepolymer is reacted with polycaprolactone triol and levulinic acid derivatives for 1-3 hours. After the reaction is completed, a mixed reactant is obtained. After removing the solvent, a high-performance crystalline bio-based elastomer is obtained.

[0013] The embodiments of the present invention also provide the aforementioned high-performance crystalline bio-based elastomer in the preparation of recyclable elastomers.

[0014] The present invention also provides a method for regulating the crystallinity of the high-performance crystalline bio-based elastomer prepared by the aforementioned preparation method.

[0015] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0016] (1) Starting from bio-based monomers, this invention prepares a high-performance crystalline bio-based elastomer that combines flexibility and rigidity, so that the prepared high-performance crystalline bio-based elastomer has excellent comprehensive performance and can effectively solve the current dilemma of polyurethane's excessive reliance on petroleum-based raw materials.

[0017] (2) The urethane bonds present in the structure can be recycled and reused; in particular, the process for preparing high-performance crystalline bio-based elastomers provided by the present invention is not only simple, but also highly operable, easy to implement and realize industrial production.

[0018] (3) The high-performance crystalline bio-based elastomer in this invention is of green biological origin, has excellent mechanical properties, and has an elongation at break of more than 3000%. Moreover, the preparation process is simple and highly operable, and it can be used in the application of highly elastic soft materials.

[0019] (4) By adopting the technical solution of the present invention, a furan ring structure is introduced into the polyurethane structure, which not only has a certain antibacterial activity, but may also undergo photochemical reaction under the action of light, thereby triggering the decomposition of the entire molecule, realizing the degradation of the molecule, and improving the environmental protection and safety of polyurethane products. Attached Figure Description

[0020] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0021] Figure 1 This is an infrared characterization image of the high-performance crystalline bio-based elastomer in Embodiment 1 of the present invention.

[0022] Figure 2 These are the DSC diagrams of embodiments 1 to 4 of the present invention.

[0023] Figure 3 This is the 1H NMR spectrum of methyl 4,4′-bis(5-amino-2-furanyl)valerate prepared in Example 1 of this invention. Detailed Implementation

[0024] In view of the deficiencies of the prior art, the inventors of this case, through long-term research and extensive practice, have proposed the technical solution of this invention. The technical solution of this invention will be clearly and completely described below. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0025] Specifically, as one aspect of the technical solution of the present invention, the method for preparing a high-performance crystalline bio-based elastomer includes: at least a levulinic acid derivative, polycaprolactone diol, isocyanate, polycaprolactone triol and a catalyst undergoing a polymerization reaction to obtain a high-performance crystalline bio-based elastomer; wherein the levulinic acid derivative contains a diamine structure.

[0026] In a preferred embodiment, the levulinic acid derivative is 4,4′-bis(5-amino-2-furanyl)valerate.

[0027] In some specific embodiments, the levulinic acid derivative includes, but is not limited to, any one of methyl 4,4′-bis(5-amino-2-furanyl)valerate and ethyl 4,4′-bis(5-amino-2-furanyl)valerate.

[0028] In some preferred embodiments, the levulinic acid derivative is methyl 4,4′-bis(5-amino-2-furanyl)valerate; methyl 4,4′-bis(5-amino-2-furanyl)valerate has the structure shown in formula (I):

[0029]

[0030] Specifically, taking methyl 4,4′-bis(5-amino-2-furanyl)valerate as an example, the preparation route for high-performance crystalline bio-based elastomers is as follows:

[0031]

[0032] As can be seen from the above reaction mechanism, on the one hand, by using bio-based methyl 4,4′-bis(5-amino-2-furanyl)valerate as a raw material, the dependence on petroleum-based raw materials can be reduced. At the same time, the synthesized polyurethane elastomer contains urethane bonds, which makes it recyclable and reprocessable. Moreover, it can be gradually degraded into small molecules for recycling and reuse, for example, it can be used as a raw material to synthesize new polymers or other chemical products.

[0033] In some preferred embodiments, the polycaprolactone diol is any one or a combination of polycaprolactone diol 1000, polycaprolactone diol 2000, or polycaprolactone diol 3000, and is not limited thereto.

[0034] In this context, polycaprolactone diol 1000 indicates that the average molecular weight of polycaprolactone diol is 1000, polycaprolactone diol 2000 indicates that the average molecular weight of polycaprolactone diol is 2000, and so on.

[0035] In some preferred embodiments, the isocyanate is any one or a combination of hexamethylene diisocyanate, isophorone diisocyanate, diphenylmethane diisocyanate, and lysine diisocyanate.

[0036] In some preferred embodiments, the polycaprolactone triol is any one or a combination of polycaprolactone triol 650 and polycaprolactone triol 750, but is not limited thereto.

[0037] Polycaprolactone Triol 550 indicates that the average molecular weight of polycaprolactone triol is 550, and so on.

[0038] In some preferred embodiments, the catalyst is an organotin compound or a tertiary amine compound.

[0039] Preferably, the catalyst is any one or a combination of dibutyltin dilaurate, triethanolamine, and triethylamine.

[0040] In some preferred embodiments, the molar ratio of polycaprolactone diol to isocyanate is (1-2):(2.2-4.4).

[0041] In some preferred embodiments, the molar ratio of polycaprolactone diol to polycaprolactone triol is (1-2):(2-4).

[0042] In some preferred embodiments, the molar ratio of polycaprolactone diol to levulinic acid derivative is (1-2):(0.2-0.4).

[0043] In some preferred embodiments, the mass ratio of the catalyst to polycaprolactone diol is (2-4):1000.

[0044] In some preferred embodiments, the preparation method specifically includes removing water from polycaprolactone diol under vacuum at 100-110°C for 1-2 hours, and then cooling it to 60-80°C.

[0045] In some preferred embodiments, the preparation method specifically includes cooling polycaprolactone diol to 60-80°C, adding isocyanate and catalyst, and reacting for 3-5 hours to obtain an isocyanate-terminated prepolymer.

[0046] In some preferred embodiments, the preparation method specifically includes cooling the prepolymer to room temperature, adding solvent-diluted polycaprolactone triol and levulinic acid derivatives, and continuing the reaction for 1-3 hours.

[0047] In some preferred embodiments, the preparation method specifically includes depositing the final mixture onto a plate and evaporating the solvent to obtain a thin film.

[0048] Furthermore, the mixture is placed in a vacuum environment before film deposition to remove air bubbles.

[0049] In some more specific embodiments, the method for preparing the high-performance crystalline bio-based elastomer includes:

[0050] 1) Remove water from polycaprolactone diol by vacuuming for 1-2 hours, then cool it to 60-80℃.

[0051] Furthermore, the molecular weight of the polycaprolactone diol is any one or a combination of 1000, 2000, or 3000.

[0052] Furthermore, the temperature during vacuuming is 100-110℃.

[0053] 2) Add isocyanate and catalyst and react for 3-5 hours to obtain isocyanate-terminated prepolymer.

[0054] Furthermore, the isocyanate is any one or a combination of hexamethylene diisocyanate, isophorone diisocyanate, diphenylmethane diisocyanate, and lysine diisocyanate.

[0055] Furthermore, the catalyst is any one or a combination of dibutyltin dilaurate, triethanolamine, and triethylamine.

[0056] Furthermore, the molar ratio of polycaprolactone diol to isocyanate is (1-2):(2.2-4.4).

[0057] Furthermore, the mass ratio of the catalyst to polycaprolactone diol is (2-4):1000.

[0058] Furthermore, the reaction temperature in step 2) is 60-80℃.

[0059] 3) After the prepolymer is cooled to room temperature, polycaprolactone triol and levulinic acid derivative diluted with solvent are added to continue the reaction.

[0060] Furthermore, the molecular weight of polycaprolactone triol is any one or a combination of 550, 650, and 750.

[0061] Furthermore, the levulinic acid derivative is methyl 4,4′-bis(5-amino-2-furanyl)valerate.

[0062] Furthermore, the molar ratio of polycaprolactone diol to polycaprolactone triol is (1-2):(2-4).

[0063] Furthermore, the molar ratio of polycaprolactone diol to levulinic acid derivative is (1-2):(0.2-0.4).

[0064] Furthermore, the reaction time continues for 1-3 hours.

[0065] 4) Place the mixture obtained in step 3) on a plate to form a film.

[0066] Furthermore, air bubbles are removed by vacuuming before placing the plate.

[0067] Furthermore, the solvent removal temperature on the plate is 60°C, and the curing time in the vacuum oven is 24 hours.

[0068] The present invention provides a high-performance crystalline bio-based elastomer prepared by the aforementioned method.

[0069] In some specific embodiments, taking methyl 4,4′-bis(5-amino-2-furanyl)valerate as an example, the structure of the high-performance crystalline bio-based elastomer prepared is shown in formula (II):

[0070]

[0071] Furthermore, the tensile strength of the high-performance crystalline bio-based elastomer cured product is 30-40 MPa, and the elongation at break is 2500-4000%.

[0072] Furthermore, the high-performance crystalline bio-based elastomer prepared by this invention can be reprocessed at high temperatures.

[0073] The technical solution of the present invention will be further described in detail below with reference to several preferred embodiments and accompanying drawings. This embodiment is implemented on the premise of the technical solution of the invention, and provides detailed implementation methods and specific operation processes. However, the protection scope of the present invention is not limited to the following embodiments.

[0074] Unless otherwise specified, the experimental materials used in the examples below can be purchased from conventional biochemical reagent companies.

[0075] Example 1

[0076] This embodiment provides a high-performance crystalline polyurethane elastomer, and the specific preparation steps include:

[0077] 1. Provides methyl 4,4′-bis(5-amino-2-furanyl)valerate.

[0078] 4,4′-bis(5-amino-2-furanyl)valerate methyl acetate was prepared by the hydroxyalkylation reaction of methyl acetate and furfurylamine. The specific steps were as follows: 10 g of furfurylamine was added to 20 mL of concentrated hydrochloric acid, and the mixture was magnetically stirred at 0 °C for 30 min. Then, 6.5 g of methyl acetate was added. The mixture was gradually heated to 60 °C and reacted for 24 h. After the reaction was complete, the mixture was diluted with ethanol, filtered, and 4,4′-bis(5-amino-2-furanyl)valerate methyl acetate hydrochloride was obtained. Reduction with sodium hydroxide yielded diamino-4,4′-bis(5-amino-2-furanyl)valerate methyl acetate. The 1H NMR spectrum is shown below. Figure 3 As shown, the synthesis of methyl 4,4′-bis(5-amino-2-furanyl)valerate was successful.

[0079] 2. Pretreatment

[0080] 4g of polycaprolactone diol (molecular weight 2000) was placed in a flask and heated to 110°C. The flask was then vacuum-sealed to remove water and magnetically stirred. After 3 hours, the temperature was lowered to 70°C to prevent the water in the polycaprolactone diol from reacting with the isocyanate.

[0081] 3. Preparation of isocyanate-terminated prepolymers

[0082] 0.7 g of hexamethylene diisocyanate diluted with 8 mL of N,N-dimethylformamide solvent was added to pretreated polycaprolactone diol, along with 2 drops of dibutyltin dilaurate as a catalyst (the mass ratio of catalyst to polycaprolactone diol was 3:1000). The mixture was heated to 80 °C for 3 hours under nitrogen protection to obtain isocyanate-terminated prepolymer.

[0083] 4. High-performance crystalline bio-based elastomers

[0084] The isocyanate-terminated prepolymer was cooled to 25°C, and 0.06 g of methyl 4,4′-bis(5-amino-2-furanyl)valerate and 0.66 g of polycaprolactone triol with a molecular weight of 550 were added. The isocyanate-terminated prepolymer obtained from polycaprolactone triol reacted with polycaprolactone triol and levulinic acid derivatives. The molar ratio of amino (methyl 4,4′-bis(5-amino-2-furanyl)valerate) to hydroxyl (polycaprolactone triol) reacting with the isocyanate group was 1:9. The reaction was continued for 5 hours under a nitrogen atmosphere until the reaction was completed. The mixture of the above reaction was evacuated to remove air bubbles, poured into a mold, and placed on a hot table at 60°C for 6 hours to remove the solvent. Then it was placed in a vacuum oven at 60°C for 24 hours to cure. After cooling to room temperature, a polyurethane elastomer was obtained, named PUE9-1.

[0085] The elastomer was tested and found to have a glass transition temperature of -50℃, an elongation at break of 4000%, a tensile strength of 30MPa, and a crystallinity of 26.4% as determined by DSC testing. Furthermore, the sample can be obtained through remolding and recycling.

[0086] Example 2

[0087] This embodiment provides a high-performance crystalline polyurethane elastomer, and the specific preparation steps include:

[0088] This embodiment uses methyl 4,4′-bis(5-amino-2-furanyl)valerate prepared by the method in Example 1.

[0089] Then, the polycaprolactone diol is pretreated. The specific steps include: placing 4g of polycaprolactone diol (molecular weight of 2000) in a flask, heating it to 110°C, removing water under vacuum, stirring magnetically, and cooling it to 70°C after 3 hours to pretreat the polycaprolactone diol.

[0090] 0.7 g of hexamethylene diisocyanate diluted with 8 mL of N,N-dimethylformamide solvent was added to the treated polycaprolactone diol, and 2 drops of dibutyltin dilaurate were added as a catalyst (mass ratio of catalyst to polycaprolactone diol ~3:1000). The mixture was heated to 80 °C for 3 hours under nitrogen protection to obtain the isocyanate-terminated prepolymer.

[0091] The temperature was then lowered to 25°C, and 0.12 g of methyl 4,4′-bis(5-amino-2-furanyl)valerate and 0.58 g of polycaprolactone triol (molecular weight 550) containing amino and hydroxyl groups that react with the isocyanate groups were added. The reaction was continued for 5 hours under a nitrogen atmosphere. After the reaction was completed, the solution was evacuated to remove air bubbles. The mixture was poured into a mold and placed on a 60°C hot plate for 6 hours to allow the solvent to evaporate. Then, it was placed in a 60°C vacuum oven for curing for 24 hours. After cooling to room temperature, the elastomer was obtained and named PUE8-2.

[0092] The elastomer was tested and found to have a glass transition temperature of -54℃, an elongation at break of 3000%, a tensile strength of 20MPa, and a crystallinity of 25.0% as determined by DSC testing. Furthermore, the sample can be obtained through remolding and recycling.

[0093] Example 3

[0094] This embodiment provides a high-performance crystalline polyurethane elastomer, and the specific preparation steps include:

[0095] This embodiment uses methyl 4,4′-bis(5-amino-2-furanyl)valerate prepared by the method in Example 1.

[0096] Then, the polycaprolactone diol was pretreated by placing 4g of polycaprolactone diol (molecular weight 2000) in a flask, heating it to 110°C, removing water under vacuum, stirring magnetically, and cooling it to 70°C after 3 hours.

[0097] Then, 0.7 g of hexamethylene diisocyanate diluted with 8 mL of N,N-dimethylformamide solvent was added, along with 2 drops of dibutyltin dilaurate as a catalyst (the mass ratio of catalyst to polycaprolactone diol was ~3:1000). The mixture was heated to 80 °C for 3 hours under nitrogen protection to obtain the isocyanate-terminated prepolymer.

[0098] Next, the temperature was lowered to 25°C, and 0.18g of methyl 4,4′-bis(5-amino-2-furanyl)valerate and 0.51g of polycaprolactone triol with a molecular weight of 550 were added (the molar ratio of amino to hydroxyl groups reacting with the isocyanate group was 3:7). The reaction was continued under a nitrogen atmosphere for 5 hours. After the reaction was completed, the solution was evacuated to remove bubbles. A suitable mold was selected, and the mixture of the above reaction was poured into the mold and placed on a hot table at 60°C for 6 hours to evaporate the solvent. Then, it was placed in a vacuum oven at 60°C for 24 hours to cure. After cooling to room temperature, the elastomer was obtained and named PUE7-3.

[0099] The elastomer was tested and found to have a glass transition temperature of -56℃, an elongation at break of 2700%, a tensile strength of 15MPa, and a crystallinity of 24.2% as determined by DSC testing. Furthermore, the sample can be obtained through remolding and recycling.

[0100] Example 4

[0101] This embodiment provides a high-performance crystalline polyurethane elastomer, and the specific preparation steps include:

[0102] In this embodiment, polycaprolactone diol is first pretreated by placing 4g of polycaprolactone diol (molecular weight 2000) in a flask, heating it to 110°C, removing water under vacuum, stirring magnetically, and then cooling it to 70°C after 3 hours.

[0103] Add 0.7 g of hexamethylene diisocyanate diluted with 8 mL of N,N-dimethylformamide solvent to the treated polycaprolactone diol, and add 2 drops of dibutyltin dilaurate as a catalyst. Heat to 80 °C for 3 hours under nitrogen protection.

[0104] The temperature was then lowered to 25°C, and 0.73g of polycaprolactone triol with a molecular weight of 550 was added. The reaction was continued for 5 hours under a nitrogen atmosphere. After the reaction was completed, the solution was evacuated to remove air bubbles. A suitable mold was selected, and the mixture from the above reaction was poured into the mold and placed on a hot plate at 60°C for 6 hours to evaporate the solvent. Then, it was placed in a vacuum oven at 60°C for 24 hours to cure. After cooling to room temperature, the elastomer was obtained and named PUE10-0.

[0105] The elastomer was tested and found to have a glass transition temperature of 48℃, an elongation at break of 3500%, a tensile strength of 14MPa, and a crystallinity of 26.5% as determined by DSC testing. Furthermore, the sample can be obtained through remolding and recycling.

[0106] Table 1. DSC crystallization data for four types of PUE

[0107]

[0108]

[0109] DSC analysis of the four PUE samples revealed that the crystallinity of PUE gradually decreased with the addition of methyl 4,4′-bis(5-amino-2-furanyl)valerate.

[0110] See Figure 2 The figures show the DSC diagrams for Examples 1-4. As can be seen from the figures, the glass transition temperature of each example is below 40°C, indicating that the PUE prepared using the technical solution of the present invention has good elasticity and toughness.

[0111] Comparative Example 1

[0112] The only difference between this comparative example and Example 1 is that polyethylene glycol 2000 is used in this comparative example instead of polycaprolactone diol 2000 in Example 1. The other components, including isocyanate and polycaprolactone triol, are the same as in Example 1, and the curing procedure is also the same.

[0113] The elastomer prepared in this comparative example did not exhibit crystallization, and its tensile strength was 13 MPa, with an elongation at break of 1000%.

[0114] Comparative Example 2

[0115] The only difference between this comparative example and Example 1 is the amount of methyl 4,4′-bis(5-amino-2-furanyl)valerate added.

[0116] Specifically, in step 4, after the isocyanate-terminated prepolymer is cooled to 25°C, the molar ratio of methyl 4,4′-bis(5-amino-2-furanyl)valerate to polycaprolactone triol with a molecular weight of 550 is 4:6. When too much methyl 4,4′-bis(5-amino-2-furanyl)valerate is added, physical entanglement is likely to occur, which prevents polycaprolactone triol from participating in the reaction and makes it difficult to prepare a film.

[0117] In addition, the inventors of this case also conducted experiments with other raw materials, process operations, and process conditions described in this specification, referring to the aforementioned embodiments, and obtained relatively ideal results in all cases.

[0118] It should be understood that the technical solutions of the present invention are not limited to the specific embodiments described above. Any technical modifications made to the technical solutions of the present invention without departing from the spirit and scope of the claims are within the scope of protection of the present invention.

Claims

1. A method for preparing a high-performance crystalline bio-based polyurethane elastomer, characterized in that, The specific steps include: at least polymerizing levulinic acid derivatives, polycaprolactone diol, isocyanate, polycaprolactone triol and catalyst to obtain a high-performance crystalline bio-based elastomer; The levulinic acid derivative contains a diamine structure.

2. The preparation method according to claim 1, characterized in that: The levulinic acid derivative is 4,4'-bis(5-amino-2-furanyl)valerate.

3. The preparation method according to claim 1, characterized in that: The levulinic acid derivative is either methyl 4,4'-bis(5-amino-2-furanyl)valerate or ethyl 4,4'-bis(5-amino-2-furanyl)valerate.

4. The preparation method according to claim 1, characterized in that: The polycaprolactone diol is any one or a combination of polycaprolactone diol 1000, polycaprolactone diol 2000, and polycaprolactone diol 3000. And / or, the isocyanate includes any one or more combinations of hexamethylene diisocyanate, isophorone diisocyanate, diphenylmethane diisocyanate, and lysine diisocyanate; And / or, the polycaprolactone triol is any one or a combination of polycaprolactone triol 550, polycaprolactone triol 650, and polycaprolactone triol 750; And / or, the catalyst is an organotin compound or a tertiary amine compound.

5. The preparation method according to claim 1, characterized in that: The molar ratio of the polycaprolactone diol to the isocyanate is (1-2):(2.2-4.4); And / or, the molar ratio of the polycaprolactone diol to the polycaprolactone triol is (1-2):(2-4); And / or, the molar ratio of the polycaprolactone diol to the levulinic acid derivative is (1-2):(0.2-0.4); And / or, the mass ratio of the catalyst to the polycaprolactone diol is (2-4):1000.

6. The preparation method according to claim 1, characterized in that, The specific steps include: S1. The isocyanate and the catalyst are added to the polycaprolactone diol to carry out a prepolymerization reaction to obtain an isocyanate-terminated prepolymer; S2. After cooling the isocyanate-terminated prepolymer to room temperature, it is further subjected to a condensation reaction with the polycaprolactone triol and the levulinic acid derivative. After the reaction is completed, a mixed reactant is obtained. S3. After removing the solvent from the mixed reactants, the high-performance crystalline bio-based polyurethane elastomer is obtained.

7. The preparation method according to claim 6, characterized in that, S1 also includes pretreatment of the polycaprolactone diol; And / or, the pretreatment includes vacuum dehydration at 100-110°C for 1-2 hours, followed by cooling to 60-80°C; And / or, the conditions for the prepolymerization reaction include reacting at 80–100°C for 3–5 hours; In S2, the condensation reaction conditions include reacting for 3-5 hours under a nitrogen atmosphere; In S3, the solvent removal includes heating at 60–80°C for 4–8 hours.

8. A high-performance crystalline bio-based polyurethane elastomer, prepared by the preparation method according to any one of claims 1-7.

9. The high-performance crystalline bio-based elastomer according to claim 8, characterized in that, The glass transition temperature of the high-performance crystalline bio-based polyurethane elastomer is -60 to 50°C. The tensile strength is 20-40 MPa, and the elongation at break is 2500-4000%.

10. The application of a high-performance crystalline bio-based polyurethane elastomer as described in claim 8 in building materials, transportation materials, food packaging materials, or medical materials.

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